Step 1
Preheat the oven to 180°C/fan oven 160°C/Gas Mark 4. Grease a 23cm (9in)

Step 2
Put the Trex, sugar, eggs, almond essence, lemon zest and lemon juice into a large mixing bowl. Add the ground almonds, polenta, salt and baking powder. Use a wooden spoon to beat together until smooth and creamy, about one to two minutes.

Step 3
Transfer to the prepared tin and level the surface. Bake on the middle shelf of the oven for 40-45 minutes, or until a fine skewer inserted into the centre of the cake comes out clean. Cool in the tin for 20 minutes, then transfer to a wire rack to cool completely.

Step 4
To decorate, mix the icing sugar with the lemon zest and lemon juice to make a thin icing. Drizzle over the cake and decorate with lemon jelly slices. Leave until set, then serve.